The purpose of this study was to identify independent associations between medication given during labor and delivery and development in the offspring. Items from pediatric and psychomotor examinations in the first year were analysed in a cohort of normal births. Infants of women given inhalant anesthetics had increased frequencies of palpable liver and spleen, and deficits in motor development as compared with infants of women given regional anesthetics. Relationships between obstetrical medication and late physical and cognitive development in this cohort are also being analysed.